Ryu sits next to 3 phonetic neighbors — Drew, Lew, and Rue are the closest matches by sound. Most share Ryu's Japanese cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"flow, current, stream"
"little fire, fiery one"
"oak tree"
"born of fire (head of fire)"
"protected by Yahweh"
"rim of a shield"
"short form of Kipling or Christopher"
"dark-skinned, Moorish"
"warrior, battle"
"cross, crossroads"
"universal, whole"
"sword"
"elm grove"
"friendliness, sociability"
"resolute protector"
"Hawaiian form of Matthew"
"fire of God"
"crown, diadem"
"God is my strength, God will strengthen"
"may God protect"
"gift of God"
Similar sound: These names share phonetic patterns with Ryu — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Japanese origins, giving them the same cultural heritage as Ryu.
Rhythm: Ryu is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.